摘要:
The synthesis of methyl 8-tert-butyloxycarbonylamino-3-oxoindolizidine-2-carboxylate and its alkyl derivatives bearing Phe, Trp and Asp side chains at C2 position are described. These bridged bicyclic lactams, obtained with high and moderate stereocontrol at C-8a and C2, respectively, have appropriate N- and C-protecting groups making them suitable for incorporation as spacers into higher peptides.